Subs not hitting hard enough

I recently installed 2 Rockford FOsgate 10" subwoofers and a rockford fosgate amp. After installing this equipment and turning it on the subs were working but were not hitting nearly as hard or with as good quality as they should have been (i have heard this set up before and know what it should sound like) To maintain a stock look i kept my stock head unit and used a adjustable power converter to allow me to plug in the amp, some people have suggested that i have the polarity mixed up, but would it be mixed up at the power converter or subs? I'm almost certain the subs are wired right seeing as how i followed the diagram in the instructions exactly. Any help would be appreciated

Re: Subs not hitting hard enough

that happend to me once i reversed the polarity. they cancel eachother signals outt and well for me i had no bass and just alot of pitter patter movement. the confuision would be at where the wires meet the sub. lwell for me i have svc subs so my left is always positive. kinda like that. but maybe your amp just isnt getting enough ppower mabye connections arent good, make they are bridged correctly or however u wired it pending on what kind of amp. it could also be box type

Re: Subs not hitting hard enough

One of my friends had these same problems with Rockford amps. Very confusing because it seems like everything is right but its just not hitting hard. Using the stock head unit compared to an aftermarket can make a big difference, so you may want to look into that.